I know Asahi Linux exists but without Apple's (driver) support it will never reach macOS on M1 level performance.
(If someone disagrees, please compare Nouveau with proprietary Nvidia drivers.)
There was no other viable option.
Mac owners are more likely to buy iPads and iPhones and become embedded in the Apple ecosystem. That draws people into the app stores, which Apple gets a cut of, and into Apple Music and Apple TV...
If they're very successful they get you to sign up for Apple Pay and the Apple Card and get a chunk of your spend for things entirely unrelated to Apple.
If they just sell you the hardware and you can easily run Linux on it, you might not run macOS and move further into their ecosystem.
Maybe people will find a way to build ARM hackintoshes. :)
Not a particularly nice situation to be in, if you're not in the Apple ecosystem, but there's the world we live in, and the world we wish it to be. Only sometimes do those worlds overlap.
So while it's a nice boost in goodwill, it's probably small enough for Apple to safely ignore.
As horrible as this is going to sound, I'm thinking both Apple and Microsoft file that under: "Some users are not worth the trouble."
Probably OK for server users though? But Apple doesn't really make servers.
There is no incentive to facilitate introducing that hardware into an uncontrolled foreign ecosystem. Apple does not want users looking at their computer while muttering "this sucks" when "this" is an OS+UI famous for incomplete/buggy behavior.
(I've tried going all-in for Linux several times. The amount of "oh, you've got to tweak this..." makes it unusable.)
Everything else you're asking for would require them to spend significantly more money and/or engineering resources on supporting the port, and that just doesn't seem like a thing Apple's senior management would go for.
I suspect they would say if you want to run Linux you can do it in a VM and use the already debugged MacOS device drivers.
It's extra effort they don't want to go to. They spent a lot of engineering and support time working with MS on boot camp, handling (what are to them) special cases and back compatibility. They really needed it at the time, but no longer need it so make no effort in making it happen. And Apple never did linux support, it's simply that linux runs on most hardware that runs windows.
Among other things, here's a major reason why it's hard: Apple supports their hardware and software for quite a long time, but is happy to break back compatibility along the way. MS considers back compatibility critical, despite the cost. I respect both positions. But getting windows running on intel Mac hardware wasn't automatic, and required developing support for bits of code designed (by MS) for all sorts of special cases. They simply needed it, so did the work, with the cooperation of MS.